Surgical tool having a distal ratchet mechanism

ABSTRACT

A flexible clip applier includes a ratchet mechanism adapted to locate a clip pusher to a known location after deployment of a distalmost clip. In addition, the clip applier includes a flexible housing into which a train of clips may be chambered. The flexible housing is constrained from elongation when subject to tensile forces. In accord with another aspect of the invention, the jaw assembly is adapted to have relatively high mechanical leverage which facilitates tissue compression prior to application of a clip.

[0001] This application is a continuation-in-part of U.S. Ser. No.10/010,906, filed Dec. 6, 2001, which is a continuation-in-part of U.S.Ser. No. 09/891,775, filed Jun. 25, 2001, which are hereby incorporatedby reference herein in their entireties.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates broadly to surgical instruments.Particularly, this invention relates to flexible endoscopic instrumentsfor use through an endoscope. More particularly, this invention relatesto a surgical clip applier which is adapted for use through an endoscopeand may be used to clamp and/or suture, ducts, vessels, and othertissues, to anchor a tissue, or to attach a foreign body to a tissue.

[0004] 2. State of the Art

[0005] Surgical clips are generally used to apply clamping force toducts, vessels, and other tissues. In addition, surgical clips areparticularly useful in controlling bleeding of a tissue in lieu ofsuturing or stapling where suturing or stapling is difficult.

[0006] All of the currently available surgical multi-firing clipappliers are substantially rigid devices intended to extend through atrocar port or through an incision to a surgical site requiringapplication of a clip. The devices have been rigid because a stiffpushing element has been required in order to exert the required pushingforce to move the clip over the tissue.

[0007] However, there is a substantial need for a flexible clip applier,particularly one insertable through a lumen of an endoscope. The abilityto apply clips through an endoscope would permit myriad minimallyinvasive surgical solutions to medical problems, especially those of thegastrointestinal tract. However, it is accepted theory that thetransmitted force required to advance or form a clip over tissue cannotbe produced in the distalmost end of a long flexible device that iscommonly constructed with a metal tubular coil, or polymer tube, such asan endoscopic device or catheter. For example, C. Paul Swain, MD, arecognized expert in endoscopic instruments and particularly endoscopicstapling devices, has stated that “[i]t is hard to exert more than 200 gof force on the tissue when pushing . . . . This fact is of course onefeature that makes intervention at flexible endoscopy relatively safe”.See C. Paul Swain, “What Endoscopic Accessories Do We Really Need?”,Emerging Technologies in Gastrointestinal Endoscopy, Gastrointest.Endosc., Vol. 7, No. 2, pp. 313-330 (April 1997). Yet, a pushing forcesubstantially greater than 200 g is required to push a clip overcompressed tissue. In fact, it is believed a force in excess of 500grams (1.1 lbs) is required for a satisfactory instrument, andsubstantially greater forces, e.g., in excess of 1500 grams (3.3 lbs)would be desirable.

[0008] Generally a flexible endoscopic device (e.g., a biopsy forcepsdevice) includes an outer tubular member, typically being constructed ofa metal tubular coil or a polymer tube which is poor in transmittingforces that impart tensile stresses to the outer tubular member, acontrol element longitudinally movable relative to the tubular member,an end effector coupled to the distal ends of both the tubular memberand the control element such that relative movement of the controlelement and the tubular member causes operation of the end effector, anda handle which moves the control element relative to the handle.

[0009] This type of flexible endoscopic instrument is limited in theamount of pushing force it can generate for several reasons. Compressionof a flexible control element (pushing element) tends to cause thepushing element to buckle within the outer flexible sheath of thedevice. If a relatively larger diameter flexible pushing element is usedsuch that it better resists buckling, the pushing element may impart toomuch stiffness to the flexing of the endoscopic instrument. In addition,a flexible pushing element of larger diameter is subject to greaterfrictional forces within the outer sheath which reduces the forcetransmitted from the handle to the end effector. If the flexible pushingelement is made relatively smaller in diameter, it is subject to kinkingwhich will result in little to no force transmitted to the distal end.Kinking is especially a problem in endoscopic instruments, as theendoscope and its lumen may be extended through a tortuous path. Forthese reasons and others, mechanical application of a relatively largedistal end pushing force and particularly clip application have beenabsent from the capability of flexible endoscopic tools.

[0010] In addition, it is important that the tissue about which a clipis to be applied be substantially compressed. While the jaws apply aclamping force which compresses the tissue, large clamping forces aredifficult to achieve due to the dimensions of the relatively small jawassembly. That is, the dimensions are such that the lever arm between apivot of the jaw assembly and each jaw tang is relatively short,limiting the mechanical leverage on the jaw assembly.

SUMMARY OF THE INVENTION

[0011] It is therefore an object of the invention to provide a flexibleendoscopic device capable of being subject to large tensile forces.

[0012] It is also an object of the invention to provide a flexibleendoscopic device capable of generating a relatively large clampingforce at its jaw assembly.

[0013] It is another object of the invention to provide a flexibleendoscopic device having a jaw assembly with increased mechanicaladvantage.

[0014] It is a further object of the invention to provide a flexibleendoscopic device which has a reliable ratchet mechanism at its distalend.

[0015] It is an additional object of the invention to provide a flexibleendoscopic clip applier which is adapted to store a plurality of clipsand which can controllably dispense the clips one at a time overcompressed tissue.

[0016] It is yet another object of the invention to provide a flexibleendoscopic clip applier which is torqueable.

[0017] In accord with these objects, which will be discussed in detailbelow, a surgical clip applier is provided having a flexible, preferablyflat wire wound outer tubular coil, a pair of jaws rotatable about aclevis at the distal end of the tubular coil, a set of end effectorwires extending through the outer tubular coil and coupled to the jaws,and a clip-advancing wire extending through the tubular coil.

[0018] A lubricious, preferably extruded polymer, multilumen barriersheath extends within the tubular coil and separates the wires from eachother and the tubular coil.

[0019] A clip chamber is provided in the distal end of the tubular coiland stores a plurality of linearly arranged clips. According to oneembodiment of the clip chamber, the clip chamber comprises a separatetubular member coupled to the distal end of the tubular coil. Theseparate tubular member may be another coil, and preferably a flat woundcoil, or may be a helically cut tube in which each helical winding isinterlocked with an adjacent winding such that the tube is flexible yetwill not elongate when subject to tensile force.

[0020] A clip pusher is provided at a distal end of the clip-advancingwire, and adapted to advance the clips in the chamber toward the jawswhen the clip-advancing wire is advanced through the barrier sheath andouter tubular coil. According to a preferred aspect of the invention,the clip pusher and clip chamber cooperate to provide a ratchetmechanism whereby clips may be distally advanced therethrough but areprevented from proximal retraction through more than a predefineddistance. Thus, the clip pusher and clips in the chamber can bewithdrawn to respective known positions after the successive deploymentof a distalmost clip. This permits the clip pusher to be located at aknown position within the clip chamber regardless of the degree offlexion to which the endoscopic clip applier is subject. According to afirst embodiment of the ratchet mechanism, notches are provided in theclip-advancing wire and a resilient catch is provided to a keyholeelement within the tubular coil. The clip-advancing wire may be moveddistally relative to the catch, but the catch limits retraction of theclip-advancing wire. According to a second embodiment of the ratchetmechanism, a ratchet structure is provided to the clip-advancing wireand a pawl is fixed to a mount which is longitudinally disposed betweentwo sections of the outer tubular member, i.e., the coil and the clipchamber. According to a third embodiment of the ratchet mechanism, twolongitudinally extending brackets are disposed within a distal portionof the outer tubular member. The brackets include flexible arms whichextend into the chamber and limit retraction of the clip pusher afteradvancement past a pair of the arms. As such, each ratchet mechanismcontrollably locates the pusher within the outer tubular member. Inaddition, in each of the embodiments, structure is provided to permittransmission of torque from the clip-advancing wire or clip pusher tothe outer tubular member, and thus the jaw assembly.

[0021] The jaws include clamping surfaces which operate to compresstissue between the jaws when the jaws are closed, guides in which adistalmost clip rides distally and is advanced over the clamped tissuewhen the line of clips is advanced by the clip pusher, and a distalanvil which operates to bend a portion of the distalmost clip to enhanceits retention on the clamped tissue. According to a preferred aspect ofthe invention, portions of the jaws and the clevis define acircumferential ridge of greater diameter than the remainder of the jawsand clevis. This ridge operates to permit the pivot axis of the jaws andthe tang holes of the jaws (at which the control wires are coupled tothe tang of the jaws) to be moved further apart than otherwise possibleto effect substantially greater mechanical advantage in closing thejaws.

[0022] A proximal handle is provided for movement of the clip-advancingwire and end effector wires relative to the barrier sheath to effect (1)clamping and rotation of the jaws (relative to each other and about thelongitudinal axis of the tubular coil), and (2) advancement of theclip-advancing wire to effect distal movement of a clip.

[0023] The flat wire wound tubular coil is preferred over round wire(though not necessarily required over a round wire wound tubular coil)because it is flexible, yet sufficiently longitudinally stiff such thatthe device may be pushed through the lumen of the endoscope. Inaddition, the flat wire wound tubular coil can be made with a highpreload and has a tensile spring constant sufficiently high that itresists buckling and uncoiling during application of a pushing force bythe handle against the clip-advancing wire. The clip-advancing wire hasa sufficiently large diameter to transmit force, yet small enough tominimize internal friction when moved within a device flexed through atortuous path in an endoscope. The end effector wires are large enoughto handle the high closing force from the handle, and to resistcompressive buckling when moved in an opposite direction, yet smallenough to be coupled to diminutive jaws. The multilumen barrier sheathsupports the clip-advancing wire and end effector wires along theirlength to reduce compressive buckling, and provides a separation layerto reduce friction. Movement of the clip-advancing wire relative to theouter tubular coil causes a compressive force in the clip-advancing wireand tensile forces in the outer tubular member such that a relativepushing force is transmitted to the distal end of the clip-advancingwire in excess of the perceived threshold of the 200 grams (0.44 lbs).In fact, one embodiment of the device of the invention, sized forendoscopic use, provides a pushing force in excess of 2267 grams (5lbs).

[0024] In operation, the jaws can be moved through a working channel ofan endoscope in a closed position. Once exited, the handle can beoperated to open the jaws and rotate the jaws to a desired orientation.The jaws are positioned on either side of tissue about which it isdesired to place a clip and the handle is operated to pull the endeffector wires such that the jaws clamp about the tissue. The handle isthen locked to maintain the jaws in the clamped position. The handle isoperated to effect advancement of the clip-advancing wire through thetubular coil such that a clip is advanced through the jaw guides andover the tissue. The clip is advanced until a portion thereof is forcedagainst the anvil of the jaws to effect bending of the clip portion suchthat that portion moves laterally to pierce the clamped tissue. Afterthe clip is applied, the jaws are released from about the tissue, andthe end effector assembly may then be moved to another tissue locationto apply additional clips.

[0025] Additional objects and advantages of the invention will becomeapparent to those skilled in the art upon reference to the detaileddescription taken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a partial section side elevation view of a surgical clipapplier according to the invention, shown with the handle configured toprovide the jaws in an open configuration;

[0027]FIG. 2 is a broken perspective view of a distal portion of theclip applier according to the invention;

[0028]FIG. 2A is an exploded and broken perspective view of a distalportion of the clip applier according to the invention;

[0029]FIG. 2B is a broken schematic view of a distal end of theclip-advancing wire and the coil connector;

[0030]FIG. 2C is a broken schematic view of a distal end of theclip-advancing wire and the coil connector illustrating the limitationon proximal movement of the clip-advancing wire relative to the coilconnector;

[0031]FIG. 3 is a perspective view of the jaw assembly of the clipapplier according to the invention, and a clip;

[0032]FIG. 4 is a partial section side elevation view of a surgical clipapplier according to the invention, showing the right side of the handlepositioned to place the jaws in an unloaded closed configuration;

[0033]FIG. 4A is a view similar to FIG. 4, illustrating alternativeembodiments to the handle of the clip applier according to theinvention;

[0034]FIG. 5 is an enlarged view of the handle of the surgical clipapplier with the handle in the same position as shown in FIG. 4;

[0035]FIG. 6 is a view similar to FIG. 4 of the left side of the handle;

[0036]FIG. 7 is a view similar to FIG. 6 with the addition of thevarious springs;

[0037]FIG. 8 is an enlarged broken section view of the proximal leftside of the handle of the clip applier according to the invention;

[0038]FIG. 9 is an enlarged side perspective view of the end effectorassembly;

[0039]FIG. 10 is an enlarged distal end perspective view of the endeffector assembly;

[0040]FIG. 11 is a broken partial section side elevation view of thedistal end of the clip applier according to the invention;

[0041]FIG. 12 is a view similar to FIG. 1, showing the handle configuredsuch that the jaws are in a unloaded closed position, and shown withoutthe pinion on the jaw closing lever;

[0042]FIG. 13 is a partial section perspective view of a surgical clipapplier according to the invention, illustrating rotation of the endeffector assembly by operation of the rotation knob;

[0043]FIG. 14 is a partial section side elevation view of a surgicalclip applier according to the invention, showing the jaws in a clampedconfiguration;

[0044]FIG. 15 is a partial section side elevation view of a surgicalclip applier according to the invention, showing the jaws in a clampedconfiguration and the clip-advancing lever actuated;

[0045]FIG. 16 is an enlarged partial section view of the handle of thesurgical clip applier, showing the clip-advancing lever actuated;

[0046]FIG. 17 is a longitudinal section view of the distal end of theclip applier according to the invention, shown with the jaws in a closedconfiguration and a formed clip therebetween;

[0047]FIG. 18 is a broken partial section side elevation view of thedistal end of the clip applier according to the invention, shown withthe jaws in an open configuration and a formed clip therebetween;

[0048]FIG. 19 is a broken partial section side elevation view of thedistal end of the clip applier according to the invention, shown withthe jaws in an open configuration, the formed clip released, and theretainer of a subsequent clip protruding between the jaws;

[0049]FIG. 20 is a longitudinal section view of the distal end of theclip applier according to the invention, shown with the jaws in an openconfiguration and the retainer retracted relative to the view of FIG.19;

[0050]FIG. 21 is a partial section side elevation view of a surgicalclip applier according to the invention, shown with the jaws in an openposition and a formed clip released therefrom;

[0051]FIG. 22 is a table listing dimensions for the tubular coil,clip-advancing wire, and end effector wires of six prototypes, and theresultant output force achieved with the prototype;

[0052]FIG. 23 is an efficiency plot of the prototypes described in thetable of FIG. 22;

[0053]FIG. 24 is a broken perspective view of a distal end of clipapplier device of the invention, showing second embodiments of a ratchetmechanism and clip chamber according to the invention;

[0054]FIG. 25 is an enlarged broken perspective view of a portion of theratchet mechanism of FIG. 24;

[0055]FIG. 26 is a partial broken perspective view of a distal end ofclip applier device of the invention, showing the second embodiments ofa ratchet mechanism and clip chamber according to the invention;

[0056]FIG. 27 is an enlarged partial broken perspective view of aportion of the ratchet mechanism and clip chamber of FIG. 26;

[0057]FIG. 28 is a side elevation of helical cut metal tube for use as aclip chamber in accord with the invention;

[0058]FIG. 29 is an end view of the metal tube of FIG. 28, with a clipshown within in broken lines;

[0059]FIG. 30 is a partial broken perspective view of a third embodimentof a ratchet mechanism and clip chamber, as well as an alternate jawassembly according to the invention;

[0060]FIG. 31 is a partial broken exploded perspective view similar toFIG. 30;

[0061]FIG. 32 is a perspective view of the alternate jaw assemblyaccording to the invention, with the jaws shown in an open position; and

[0062]FIG. 33 is a perspective view of the alternate jaw assemblyaccording to the invention, with the jaws shown in a closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0063] Turning now to FIGS. 1, 2, 2A and 3, an embodiment of a flexibleclip applier 10 according to the invention suitable for insertionthrough a working channel (lumen) of an endoscope is shown. The clipapplier 10 generally includes a flexible, flat wire wound outer tubularcoil 12 having an end effector assembly 13 mounted at a distal end 16thereof. The end effector assembly 13 includes a clevis (jaw mount) 14rotatably supporting a pair of jaws 18, 20. End effector wires 22, 24extend through the tubular coil 12 and have distal ends 26 respectivelycoupled to the jaws 18, 20. A clip-advancing wire 30 extends through thetubular coil 12 and includes a distal end 32 provided with a clip pusher34. A lubricious, preferably extruded, multilumen barrier sheath 36extends through substantially the entire length of the outer tubularcoil 12 and separates the end effector wires 22, 24 and clip-advancingwire 30 from each other and the outer tubular coil 12. A proximal handleassembly 40 is provided for moving the end effector wires 22, 24 andclip-advancing wire 30 relative to the tubular coil 12 to effectclamping and rotation of the jaws and advancement of a clip, asdescribed in detail below.

[0064] Referring to FIGS. 4 and 5, more particularly, the handleassembly 40 includes a housing defined by two shell portions 42, 44, astationary handle 46, a jaw closing lever 48 linearly movable within aslot 50 in the housing and relative to the stationary handle 46, and aclip-advancing lever 52 rotatably mounted on the jaw closing lever 48with a pivot pin 54. The jaw closing lever 48 is coupled to the endeffector wires 22, 24, as described in detail below. The jaw closinglever 48 is biased into an open position (away from the stationaryhandle 46) with a constant force spring 56 held in a distal portion ofthe housing such that the jaws 18, 20 are in an open configuration whenno manual force is applied against the force of the spring 56 to movethe jaw closing lever toward the stationary handle. The clip-advancinglever 52 is forced into an open position, also away from the stationaryhandle 46, with a torsion spring 58 (FIGS. 4 and 7). The clip-advancinglever 52 is coupled to the clip-advancing wire 30, as discussed indetail below, with rotation of the clip-advancing lever 52 operating tomove the clip pusher 34 at the distal end 32 of the clip-advancing wire30 longitudinally within the tubular coil.

[0065] A tube 60 extends from the interior of the handle 40 to theexterior and includes a proximal rotation knob 62. The proximal end ofthe clip-advancing wire 30 is clamped, or otherwise held, within thetube 60 such that rotation of the knob 62 causes rotation of the entireclip-advancing wire. A distal end 64 of the tube 60 is rotatably coupledwithin a collar 66. The collar 66 is fixedly coupled to a rack 68.Linear movement of the rack 68 within the housing causes the tube tomove longitudinally within and outside the housing.

[0066] Alternatively, referring to FIG. 4A, the tube 60 may betelescoping, having two rotationally interfering sections 60 a and 60 b,such that movement of the rack 68 moves a distal section 60 a of thetube relative to a proximal section 60 b, thereby maintaining a constantlength for extension of the proximal section 60 b of the tube outsidethe housing. The rotationally interfering portions, e.g., each having ahex shape, permit rotationally forces to be transmitted from the knob 62to the distal end 64 of the tube.

[0067] Referring back to FIG. 4, a pinion 70 is rotatably mounted at 72to an upper portion 74 of the clip-advancing lever 52 and positioned toact on the rack 68 when the clip-advancing lever is rotated. As such,when the clip-advancing lever 52 is rotated about pivot 54 toward thejaw closing lever 48, the rack 68 and the clip-advancing wire 30 areadvanced. The rack 68 is preferably substantially longer than what isrequired by the number of teeth on the pinion 70. As a result, thepinion 70 can act upon the rack 68 in any location at which the jawclosing lever 48 may be positioned upon closing the jaws 18, 20. This,when the jaw closing lever 48 is pulled back toward the stationaryhandle 46 to effect closure of the jaws 18, 20 about tissue, the jawclosing lever 48 may be located at a location which is consistent withthe thickness and consistency of the tissue about which the jaws are tobe closed.

[0068] The teeth of the pinion 70 are preferably at a positiveengagement angle relative to the teeth of the rack 68 because of thelocation of the pinion pivot axis 72. Then, when the pinion is rotated,the rack is moved longitudinally. A leaf spring 76 acts between thepinion 70, at hole 78, and the advancing lever 52 at shelf 77 to forcethe pinion 70 into the rack 68. After firing a clip, as discussed below,release of the clip-advancing lever 52 allows the spring 58 to returnthe lever 52 back to its unbiased position, and the pinion 70 rotatesabout the pinion axis 72 against the leaf spring 76 and over the rack68.

[0069] Turning now to FIGS. 6 through 8, the jaw closing lever 48includes a spring activated catch system 80 which locks the jaw closinglever when a predetermined load is applied thereto rather than when theclosing lever is located at any particular location. The catch system 80includes the following structures on an upper mount portion 82 of thejaw closing lever 48: a proximal spring mount 84; two spaced apart bolts86, 88; and a locking tooth 90. The locking tooth 90 includes a proximalcam 92. The catch system 80 further includes the following additionalstructures: a latch 94 having a linear slot 96 and a cam slot 98, whichare positioned over bolts 86, 88 respectively; an end effector wiremount 100 to which the proximal ends of the end effector wires 22, 24are attached; an upper cam surface 102 for the below-described leverlock 110; and a spring catch 104. An extension spring 106 (FIG. 7) isheld between the spring mount 84 and spring catch 104. A generallyL-shaped lever lock 110 is rotatably coupled about a lever pivot 114formed at the proximal end of the handle. An elongate portion 116 of thelock 110 includes a comb; i.e., the portion 116 includes a plurality ofteeth 118, each of which include a distal camming surface 120. Anotherportion 122 of the lever lock 110 is provided with a release button 124which extends outside of the handle housing. A torsion spring 130 isprovided about the pivot 114 to bias the lever lock 110 down toward thelocking tooth 90. A safety 132 is also provided to prevent release ofthe jaw closing lever 48 when the clip-advancing lever 52 is moved froman unbiased position, thereby preventing inadvertent release ofunapplied clips.

[0070] Once the jaws are closed about tissue, as discussed furtherbelow, it is desired to maintain their closed position until a clip isadvanced over the tissue. In view of this object, the catch system 80function as follows. Still referring to FIGS. 6 through 8, the camsurface 102 is generally adapted to position the teeth 118 of the leverlock 110 located in front of the locking tooth 90 above the lockingtooth, such that the jaw closing lever 48 may be moved linearly. Whenthe jaw closing lever 48 is moved toward the stationary lever 46,tension is increased in the end effector wires 22, 24 to move the jaws18, 20 from an open position to a closed position. As the tensionincreases in the end effector wires 22, 24 and exceeds the tension ofthe extension spring 106, the latch 94 moves distally relative to thejaw closing lever 48. Then, movement of the jaw closing lever 48relative to the latch 94 causes the bolts 86, 88 to ride within thelinear slot 96 and the camming slot 98, respectively. Referring to FIG.8, movement of bolt 88 within camming slot 98 forces the proximal end ofthe latch 94 downward and permits the lever lock 110 to rotateclockwise. This causes the locking tooth 90 to engage the toothedportion 116 of the lever lock 110 and lock the position of the jawclosing lever 48. The load applied to the end effector wires is thenlimited to the force applied by the extension spring 106 (FIG. 7). Thejaw closing lever 48 then may be released by pushing the release button124 sufficiently to rotate the lever lock 110 against the bias of thetorsion spring 130 and clear the locking tooth 90.

[0071] Turning now to FIGS. 1, 2, 4 and 6, the distal end of the housing42, 44 of the handle assembly 40 includes a slot 131 in which twopreferably substantially rigid and preferably low friction tubes 133,135, e.g., brass tubes, are provided. The proximal end 136 of thetubular coil 12 is coupled to the housing in alignment with the tubes133, 135 with a flare nut coupling 138 or an equivalent assembly. Theclip-advancing wire 30 extends from the rotation tube 60 through tube133 and into a clip-advancing wire lumen 140 of the barrier sheath 36.The clip-advancing wire 30 extends therethrough to the distal end 16 ofthe tubular coil 12. The end effector wires 22, 24 extend from endeffector wire mount 100 through tube 135 and into respective endeffector wire lumina 142, 144 of the barrier sheath 36, and then extendtherethrough to the distal end of the tubular coil. Wires 22, 24 and 30are provided in separate lumina within the barrier sheath 36 in order tominimize friction between the wires and reduce buckling and kinking ofthe wires along the length of the tubular coil 12.

[0072] Turning again to FIG. 4A, rather than using tubes to direct thewires from the housing into the barrier sheath in tubular coil, thehousing may be formed with channels which provide the same function. Forexample, channels 132 a, 132 b are adapted to direct the clip-advancingwire 30 and end effector wires 22, 24, respectively, into the barriersheath 36 within the tubular coil 12. In addition, the housing may beformed with distal structure, e.g., a cylindrical protrusion 146,facilitating the coupling of a flare nut assembly thereto.

[0073] Referring back to FIG. 2, the tubular coil 12 is a preferablystainless steel (or other metal or metal alloy) flat wire wound wiretubular coil, though a round wire wound tubular coil may be used. Thetubular coil 12 is fairly stiff such that the device can be pushedthrough the endoscope to the treatment area. The tubular coil 12 has aspring constant sufficiently high in order to resist uncoiling whensubject to the tensile load created when the handle applies a pushingforce to the clip-advancing wire and the clips, as discussed in moredetail below, and minimize buckling during force transmission. Inaddition, the tubular coil 12 is preloaded such that each turn issubstantially in contact with the adjacent turns 360° around the tubularcoil. The outer diameter of the tubular coil 12 has an outer diametersmaller than the inner diameter of the working channel (lumen) of anendoscope for which it is intended, and the inner diameter of thetubular coil should be maximized so that it may readily accept thebarrier sheath, and clip-advancing wire and end effector wires, as wellas clips, as discussed below. In preferred embodiments, the tubular coil12 of a device adapted for an endoscope having a 3.2 mm working channelhas an outer diameter preferably not exceeding approximately 3.175 mm(0.125 inch), and a preferably an inner diameter of at leastapproximately 0.90 mm (0.035 inch) so that it may accept the endeffector wires 22, 24, clip-advancing wire 30, barrier sheath 36, andclips 202. That is, as shown in FIG. 11, the distal end of the coildefines a clip chamber 200 for storing a train of clips 202, asdiscussed in more detail below. The inner diameter of the coil 12preferably corresponds to the transverse dimension of a clip 202,discussed below, so that the clip is stably directed through the chamber200. The wire of the tubular coil 12 has a width W preferably betweenapproximately 0.635 mm to 1.270 mm (0.025 inch to 0.050 inch), and athickness T preferably at least approximately 0.13 mm to 0.75 mm (0.005inch to 0.030 inch). The tubular coil length should at least be thelength of the endoscope working channel, generally 150 cm to 250 cm. Asubstantial length of the tubular coil 12 is preferably covered in ahigh density polyethylene (HDPE) sheath 150 (FIGS. 1, 2 and 2A).

[0074] The barrier sheath 36 within the tubular coil is preferablynon-circular in shape to reduce contact points and thereby minimizefriction between the barrier sheath and the tubular coil. The primarypurpose of the sheath is to maintain a close fitting bearing surface forthe clip-advancing wire, although its three distinct lumina help reducefriction between all the wires. The sheath 36 preferably free floatswithin the tubular coil; i.e., it is not attached to the tubular coil atits ends or along its length. Preferred cross-sectional shapes includegenerally rectangular and triangular (each with or without broken orrounded edges) and trefoil. The barrier sheath 36 is preferably anextrusion made from polypropylene, an FEP fluoropolymer resin (FEP),polytetrafluoroethylene (PTFE), high density polyethylene (HDPE), nitrolpolyvinyl chloride, nylon, or any other lubricious polymer.

[0075] The clip-advancing wire 30 is preferably made of nickel-titaniumalloy (NiTi) or stainless steel. The NiTi construction permits theclip-advancing wire 30 to transmit torque (by rotation of the rotationknob 62) without taking a cast, and with minimal whipping. Theclip-advancing wire 30 has a sufficiently large diameter to transmitforce, yet not so large that it is prevented from functioning through atortuous path or fit within the tubular coil 12. A preferred diameterfor the clip-advancing wire is approximately 0.375 mm to 0.89 mm (0.015inch to 0.035 inch).

[0076] Referring to FIGS. 2, 2A and 2B, the distal end 32 of theclip-advancing wire 30 has a non-circular cross-section, and ispreferably rectangular in shape. The distal end 32 is preferably alength four to five times the length of the clip pusher 34. A coilconnector 152 is coupled within the distal portion 16 of the tubularcoil 12, e.g., by welding, press fitting, interference fit, pinning,etc., preferably approximately 25 mm to 50 mm from the distal end of thetubular coil (i.e., the length of a linear arrangement of five or soclips), and includes a central keyhole 156 having a non-circular crosssection, and two end effector channels 158 (only one shown) throughwhich the end effector wires 22, 24 extend. The distal end 32 of theclip-advancing wire 30 can be longitudinally moved through the keyhole156, with the transition 159 of the clip-advancing wire 30 fromnon-circular to circular outer shape functioning as a stop against thekeyhole 156 for additional distal movement.

[0077] In the flexible clip applier 10 there is a need to know theprecise location of the clip pusher 34. This is rendered difficult by abending of the device, which alters the relative positions of theclip-advancing wire 30 relative to the coil 12. Thus, referring to FIG.2B, the distal end 32 of the clip-advancing wire 30 also includes aratchet mechanism partially defined by notches 250 along one side 251 ofthe distal end 32 which have a distal surface 252 substantiallyperpendicular to the side 251 and proximal beveled surface 254. Theratchet mechanism is also defined by a resilient pawl 256 on the coilconnector 152. The pawl 256 is in alignment with the notches 250. Whenthe clip-advancing wire 30 is moved distally through the keyhole 156,the pawl 256 rides against the beveled surface 254 of the notches 250,and bends for clearance. However, as distal surface 252 interferes withthe pawl 256 when the clip-advancing wire 30 is moved proximallyrelative to the coil connector 152, the clip-advancing wire 30 may notbe moved proximally by a distance which would cause a notch 250 to passthe pawl 256 (FIG. 2C). As such, after distal advancement of theclip-advancing wire and clip pusher and deployment of a clip, proximalretraction of the clip-advancing wire and clip pusher references theclip pusher to a precise predefined location.

[0078] Moreover, rotation of the clip-advancing wire 30 causes arotational moment to be applied to the connector 152 and consequentlythe distal end of the tubular coil 12. The distal end of the preloadedtubular coil 12 can be thereby rotated 360° in each of the clockwise andcounterclockwise directions by rotation of the rotation knob 62 attachedto the proximal end of the clip-advancing wire 30. Because the endeffector assembly 13 is attached to the distal end of the tubular coil,rotation of knob 62 effects rotation of the end effector assembly 13 andthe jaws 18, 20.

[0079] The end effector wires 22, 24 are large enough in diameter topreferably handle up to fifteen pounds of closing force from the handleassembly and also to handle the force required to open the jaws 18, 20without buckling. However, the end effector wires must be small enoughin diameter to attach to the jaws, and fit in the tubular coil 12. Apreferred diameter for the end effector wires is approximately 0.178 mmto 0.375 mm (0.007 inch to 0.015 inch), though other sizes may be used.

[0080] Referring to FIGS. 9 and 10, the clevis 14 of the end effectorassembly 13 is preferably coupled directly to the distal end of thetubular coil 12. The clevis 14 includes a central clip channel 164having a preferably rectangular cross section, and two lateral openings165 through which the distal ends of the end effector wires 26, 28 canrespectively exit. The jaws 18, 20 are each rotatably coupled about theclevis 14 with a respective axle 166 (one shown) which does notinterfere with the channel 164. Each jaw 18, 20 includes a proximal tang168, 169 respectively, which is coupled to the distal ends of therespective end effector wires 26, 28. The distal portion of each jaw 18,20 includes a clip guide 170, 172, respectively, and clamping surfaces174, 176 on jaw 18, and clamping surfaces 178, 180 on jaw 20 extendingalong each side of the guide 172. All of the clamping surfaces 174, 176,178, 180 preferably have proximally directed teeth 182 which pullstarget tissue toward the clip channel 164 as the jaws are closed, andalso securely grips the tissue when a clip is advanced thereover. Thedistal end of jaw 18 includes an anvil 184 which is in alignment withthe clip guide 170 which curves (or is angled) toward jaw 20. Jaw 20includes two distal anvil guides 186, 188 between which the anvil 184 ispositioned when the jaws are moved to a closed position. Jaw 20 alsodefines a distal well 190 between the anvil guides 186, 188 which islower than the surface of clip guide 172.

[0081] Referring to FIG. 11, the clip chamber 200 for storing aplurality of linearly arranged clips 202 (FIG. 2A), described furtherbelow, is formed between the coil connector 152 (FIGS. 2 and 2A) and thedistal end 16 of the tubular coil 12. The clip chamber 200 is alignedwith the clip channel 164 of the clevis 14. The clip pusher 34 isprovided at the proximal end of the chamber and situated to push on aproximalmost clip such that all clips in front of the clip pusher 34 areadvanced toward the jaws 18, 20 when the clip-advancing lever 52 isactuated to cause the clip-advancing wire 30 to move distally relativeto the tubular coil 12.

[0082] The clip pusher 34, preferably made of stainless steel, iscoupled to the distal end 32 of the clip-advancing wire 30, e.g., bymechanical joining or welding. The clip pusher 34, as described in moredetail below, is provided with a shape substantially similar to thedistal portion of a clip 202 (FIG. 2A) adapted to be used in the clipapplier. Such clips 202 are described in detail in previouslyincorporated U.S. Ser. No. 09/891,775. Generally, referring to FIG. 2A,the clips 202 are each in a generally U-shaped configuration with firstand second arms 204, 206, and a bridge portion 208 therebetween. Thefirst arm 204 extends into a deformable retainer 214 preferably havinga-tissue-piercing end 216 and preferably also a hook 218, and the secondarm 206 is provided with a tip 210 preferably having one or more catches212. The clip 202 is provided with structure that facilitates thestacking (or chaining) of a plurality of clips in the clip chamber 200.The structure includes: a notch 220 at a junction of the second arm 206and the bridge portion 208 which is adapted to receive the tip 210 ofthe second arm 206 of another clip; an elongate recess 222 along theexterior of the first arm 204 which is adapted to receive the retainer214 of the first arm of another clip; and an interior configuration 224at the ends of the first and second arms which corresponds to anexterior shape of the proximal bridge portion 208 of another clip. Inone embodiment, the clips 202 are each approximately 6.86 mm (0.27 inch)in length from the bridge 208 to the end of the retainer 214, have awidth of approximately 0.90 mm (0.035 inch), and a height of 1.80 mm(0.070 inch). However, it is understood that the clip dimensions may beadapted for use in devices having tubular coil inner diameters ofvarious sizes.

[0083] Referring to FIGS. 2 and 2A, the clip pusher 34 includes a rearclip seat 228 which corresponds to the exterior shape of the proximalend of the clip. The clip pusher 34 also includes a distally extendingarm 230 having a distal clip catch 232 (adapted to seat in the recess222 of clip 202), and a shoulder 234 adjacent the clip seat 228 on theside opposite the arm 230. As such, the clip pusher 34 includesstructure which is adapted to conform the proximal end of a clip 202 fortransferring a pushing force relative to the tubular coil. In addition,the clip catch 232, by engaging in the recess 222 of a clip 202,prevents clips from unintentionally moving distally. The clip catch alsopermits moving a clip 202 proximally, by retracting the clip pusher 34such that the clip catch 232 forces back against wall at the rear of therecess 222 and pulls the engaged clip proximally, which in turn movesother clips in the ‘chain’. The operation of the distal portion of thedevice 10 (including the end effector assembly 13, the clip pusher 34,and the clip chamber 200) will become evident with reference to thefollowing description of the use of the device 10.

[0084] Referring to FIGS. 4 and 12, the jaw closing lever 48 is movedtoward the stationary handle 46, against the bias of spring 56, to causethe jaws 18, 20 of the end effector 13 to move into a closed position.Movement of the lever 48 adapts, in size, the distal end of the devicefor delivery through the lumen (working channel) of an endoscope, butpreferably does not substantially load the end effector wires 22, 24.Once the end effector assembly 13 has exited the distal end of theendoscope, the jaw closing lever 48 can be released to open the jaws(FIG. 1). Referring now to FIG. 13, the proximal rotation knob 62 can berotated which, as discussed above, effects rotation of the entireclip-advancing wire 30 and, hence, rotation of the end effector assembly13. Briefly, this is because the end effector assembly 13 is coupled tothe tubular coil 12 and the tubular coil is provided with a fixed coilconnector 152 which is rotated by rotation of the distal end 32 of theclip-advancing wire 30.

[0085] Turning now to FIG. 14, once the jaws 18, 20 of the end effectorassembly 13 are positioned on either side of tissue (not shown) aboutwhich it is desired to place a clip 202 (FIGS. 2 and 2A), the jawclosing lever 48 is again moved toward the stationary handle 46 to clampthe jaws about the tissue. The lever 48 is moved relatively further thanshown in FIG. 12, as the wires 22, 24 will be under load to compress thetissue. Referring back to FIGS. 9 and 10, the teeth 182 on the clampingsurfaces 174, 176, 178, 180 of the jaws 18, 20 are angled proximally topull the tissue into the jaws assembly and securely hold the tissueagainst the distally directed force of an advanced clip. As the jawsclose, the anvil 184 moves between the anvil guides 186, 188, and maypartially or fully pierce the tissue.

[0086] Once the jaws are fully clamped about the tissue, the lockingtooth 90 engages with the lever lock 110 as the latch 94 moves down toallow engagement and thereby lock the jaw closing lever 48 relative tothe stationary handle 46, as discussed above with respect to FIGS. 6 and7. As discussed above, the jaws are locked based upon the load in thehandle, rather than at any particular position. This permits locking thejaws about tissues of various thicknesses and compressive properties.Moreover, it is noted that when the jaws 18, 20 are fully clamped, theend effector wires 22, 24 are placed under tension which providescompression to the tubular coil 12 such that the coil has an effectivelyhigher tensile limitation before stretching.

[0087] Referring now to FIGS. 15 and 16, after the jaws are clampedabout the tissue, the clip-advancing lever 52 is rotated about the pivotpin 54 to effect advancement of the clip-advancing wire 30 through thetubular coil 12. More particularly, as lever 52 is rotated toward thejaw closing lever 48, the pinion 70 engages the rack 68 to move the rackrelatively distally. As the proximal end of the clip-advancing wire 30is longitudinally fixed relative to the rack 68, the distal end 32 ofthe clip-advancing wire 30 is consequently moved distally. Referring toFIGS. 10 and 17, the pusher 34, at the distal end 32 of theclip-advancing wire 30 distally advances the clips 202 a, 202 b, 202 c,202 d in the chamber 200, and particularly forces the distalmost clip202 a, through the channel 164 in the clevis 14 and between the jaws 18,20. As clip 202 a is further advanced, the first and second arms 204,206 ride in guides 170, 172, respectively, and are forced over thetissue held between the jaws 18, 20. When the retainer 214 on the firstarm 204 of the clip 202 a is forced against the anvil 184, the retainer214 is bent toward jaw 20; the tip 216 pierces the tissue between thejaws 18, 20 (or is guided into the pierce hole made by the anvil 184when the jaws clamped the tissue); and the tip 216 enters the well 190at the distal end of jaw 20 to extends around the tip 210 of the secondarm 206 which overhangs the well. The hook 218 at the tip 216 of theretainer 214 may engage (although it does not necessarily engage), thelatch 212 at the distal end of the second arm 206. The force provided bythe clip-advancing wire 30 to advance a clip 202 over the clampedtissue, to bend the retainer 214 against the anvil 184, and to force thetip 216 of the retainer to pierce tissue is at least 500 grams (1.1lbs), and more typically approaches 1500 grams (3.3 lbs) or higher.

[0088] Referring now to FIGS. 6 and 18, after the clip is applied, thejaws 18, 20 are released from about the tissue. This is done by pressingthe release button 124 of the lever lock 110 such that the jaw closinglever 48 is permitted to move relative to the stationary handle 46.

[0089] Referring to FIG. 19, the clip is then released from the endeffector jaw assembly by moving the jaw assembly relative to the appliedclip 202 a. The end effector assembly may then be moved to anothertissue location to apply additional clips.

[0090] It is noted that after clip 202 a, is released, the retainer 214b of clip 202 b partially extends into the space between the jaws 18,20. If not retracted, this retainer 214 b would obstruct positioning thejaws 18, 20 about the tissue and subsequent clip application during theprocedure. However, when the clip-advancing lever 52 is released,torsion spring 58 (FIG. 4) operates to pull back the clip-advancing wire30 and the clip pusher 34 and thereby retract the ‘chain’ of clips. Thatis, the clip catch 232 of the clip pusher pulls back on clip 202 d, andthe retainer 214 d of clip 202 d pulls back clip 202 c, and so on, untilthe extending retainer 214 b is pulled within the chamber 164 of theclevis, and the space between the jaws 18, 20 is cleared, as shown inFIGS. 20 and 21. The clip-advancing wire is limited in the distance bywhich it can be retracted; it may be retracted only so far as permittedby interference of a ridge 250 on the clip-advancing wire 30 locatedjust distal the catch 256 of the coil connector 152, and the catch 256(FIG. 2B), which is constructed to be approximately the length of theprotruding retainer 214 b.

[0091] The device may then be used to apply another clip, or the jawsmay be closed and the device may be withdrawn through the endoscope.

[0092] The resulting clip applier is capable of transmitting a pushingforce at the distal end of the clip-advancing wire, resulting from thecompressive force appliable to the clip-advancing wire and the relativetensile force appliable to the outer tubular coil and end effectorwires, far in excess of the perceived threshold of the 200 grams (0.44lbs) in the prior art. In fact, as discussed below, one embodiment ofthe device of the invention provides a pushing force in excess of 2267grams (5 lbs).

[0093] More particularly, referring to FIG. 22, a table listing partdimensions of six prototype device, and the resultant output forcesachieved with prototype devices is provided. FIG. 23 provides anefficiency plot (input pushing force v. output pushing force) for theuse of the prototypes. In all prototypes, the tubular coil,clip-advancing wire, and end effector wires are made from stainlesssteel. Details of the table and the efficiency plot are discussed belowwith respect to Examples 1 through 6.

EXAMPLE 1

[0094] In a first prototype, indicated by ‘RUN #1’, ‘RUN #2’ and ‘RUN#3’, the tubular coil 12 has an outer diameter of 0.09 inch and an innerdiameter of 0.06 inch. The clip-advancing wire 30 has an outer diameterof 0.017 inch and the end effector wires 22, 24 each have an outerdiameter of 0.011 inch. The proximal end of the end effector wires 22,24 are pulled with 11 lbs of force which generally results in 5 to 10lbs of force at the distal end of the end effector wires, depending onthe degree to which the tubular coil 12 is bent (modeled by looping thetubular coil through two inch loops); i.e., frictional losses reduce thetransmitted force. Moreover, it is noted that whatever force istransmitted to the distal end of the end effector wires 22, 24, onlyapproximately one-fifth of that force is applied to the jaws, as thedistance from the jaw tang 168 to the pivot 166 is relatively shorterthan the length of the end of the jaw (anvil 184) to the pivot 166,approximately in a one to five ratio. As such, an input force of 11 lbsmay results in one to two lbs of force on the jaws 18, 20. Applying thepulling force simulates the in-use condition in which the pushing forceis transmitted.

[0095] With the tubular coil 12 extending relatively straight (i.e.,through no loops) in ‘RUN #1’, an input pushing force of 8 lbs on theproximal end of the clip-advancing wire 30 (i.e., a pushing force of 8lbs on the rack 68) resulted in an output pushing force of 3.82 lbs(1732.7 grams) at the clip pusher 34 at the distal end 32 of theclip-advancing wire 30. With the tubular coil 12 extending through onetwo-inch loop in ‘RUN #2’, an input pushing force of 8 lbs resulted inan output pushing force of 3.42 lbs (1551.3 grams). With the tubularcoil 12 extending through two two-inch loops, in ‘RUN #3’, an inputpushing force of 7 lbs resulted in an output pushing force of 3.37 lbs(1528.6 grams).

EXAMPLE 2

[0096] In a second prototype, indicated by ‘RUN #4’, the diameters ofthe tubular coil 12 and end effector wires 22, 24 are the same asExample 1. However, the diameter of the clip-advancing wire 30 isdecreased to 0.015 inch. With the tubular coil 12 extending through noloops, a six pound input pushing force resulted in an output pushingforce of 2.11 lbs (957 grams).

EXAMPLE 3

[0097] In a third prototype, indicated by ‘RUN #5’, ‘RUN #6’ and ‘RUN#7’, the diameters of the tubular coil 12 and end effector wires 22, 24are the same as Example 1. However, the diameter of the clip-advancingwire 30 is increased to 0.02 inch. With the tubular coil 12 extendingthrough no loops in ‘RUN #5’, an input pushing force of 8 lbs resultedin an output pushing force of 4.03 lbs (1828 grams). With the tubularcoil 12 extending through one two-inch loop in ‘RUN #6’, an inputpushing force of 8 lbs resulted in an output pushing force of 4.08 lbs(1851 grams). With the tubular coil extending through two two-inchloops, in ‘RUN #7’, an input pushing force of 8 lbs resulted in anoutput pushing force of 3.54 lbs (1605.7 grams).

EXAMPLE 4

[0098] In a fourth prototype, indicated by ‘RUN #8’ and ‘RUN #9’, thedevice includes a tubular coil 12 having an outer diameter of 0.086 inchand an inner diameter of 0.053 inch, a clip-advancing wire 30 having adiameter of 0.017 inch, and end effector wires 22, 24 having diametersof 0.009 inch. With the tubular coil extending through no loops, aninput pushing force of 8 lbs resulted in 4.61 lbs (2091 grams) of outputpushing force. With the tubular coil extending through two two-inchloops, an input pushing force of 8 lbs resulted in 4.28 lbs (1941.3grams) of output pushing force.

EXAMPLE 5

[0099] In a fifth prototype, indicated by ‘RUN #10’, the clip-advancingwire 30 and end effector-wires 22, 24 of the device 10 have the samediameters as Example 4. The tubular coil 12 has an outer diameter of0.086 inch and an inner diameter of 0.054 inch. With the tubular coil 12extending through no loops, an input pushing force of 8 lbs resulted in4.42 lbs (2004.9 grams) of output pushing force.

EXAMPLE 6

[0100] In a sixth prototype, indicated by ‘RUN #11’, the clip-advancingwire 30 and end effector wires 22, 24 of the device 10 have the samediameters as Example 4. The tubular coil 12 has an outer diameter of0.083 inch and an inner diameter of 0.054 inch. With the tubular coil 12extending through no loops, an input pushing force of 8 lbs resulted in5.17 lbs (2345 grams) of output pushing force.

[0101] Other flexible clip appliers suitable for use through arelatively smaller 2.6 mm diameter endoscope have also been constructedand tested. For example, one clip applier has a tubular coil 12 with anouter diameter of 0.092 inch, and an inner diameter of 0.060 inch, aclip-advancing wire 30 with a diameter of 0.022 inch, and end effectorwires 22, 24 each with a diameter of 0.013 inch. The device can apply apushing force of between 3 lbs (1361 grams) and 5 lbs (2268 grams)depending on the number of two-inch loops through which the tubular coilwas wound.

[0102] It is therefore appreciated that other dimensions may be used fordevices intended for use in endoscopes having working channels of othersizes. Moreover, the device may be used outside an endoscope, where itis not limited by the size of the working channel.

[0103] There are also alternative embodiments to various aspects of thedevice. For example, other ratchet mechanisms and clip chambers can beused. Referring to FIGS. 24 through 27, a second ratchet mechanism andsecond clip chamber according to the invention is shown. The ratchetmechanism includes ratchet 300 defined in the distal end 302 of theclip-advancing wire 30. The ratchet 300 includes a plurality ofalternating teeth 334 and notches 336 defined by shoulders 338 and ramps340. A longitudinal lower slot 304 is also defined in the distal end 302of the wire. The teeth, notches, and slot may be machined into the wire30. The distal end 302 of the wire 30 is-provided with a clip pusher 34.The distal end 302 of the wire 30 is preferably coupled to the clippusher 34 by posts 342 extending through corresponding holes 344 ineach.

[0104] The distal end 16 of the coil 12 is provided with a pawl mount346. A second flexible tubular member 310, approximately one to threeinches in length, extends between the pawl mount 346 and the jawassembly 13 to define a clip chamber 320. The second tubular member 310may be a section of a wire coil, preferably similar in construction tocoil 12. Alternatively, the second tubular member may be of asubstantially different construction, as described in detail below withrespect to FIGS. 26 and 27. Regardless, the pawl mount 346 preferablyhas substantially the same outer diameter as coil 12 and second tubularmember 310. The pawl mount 346 is fixedly coupled to the distal end 16of the coil 12 and the second tubular member 310, preferably by crimpingor welding.

[0105] The pawl mount 346 defines first and second circumferentialgrooves 348, 350. A first ring 352 is provided in the first groove 348and includes a portion extending substantially radially inward to definea resilient ratchet pawl 354. The ratchet pawl 354 extends into one ofthe notches 336 of the ratchet 300. When the clip-advancing wire 30 ismoved distally relative to the coil 12, the ratchet pawl 354 rides up aramp 340 and moves into a relatively proximal notch 336. When theclip-advancing wire 30 is moved proximally relative to the coil 12, theratchet pawl 354 will abut against a distally-adjacent shoulder 338 tolimit proximal movement to a predetermined maximum amount regardless ofthe longitudinal location of the clip pusher 34 within the clip chamber320. A second ring 356 is provided in the second groove 350 and includesa portion extending substantially radially into the slot 304. Theratchet pawl 354 and alignment pawl 358 together prevent rotation of thedistal end 302 of the wire 300 relative to the pawl mount 346. Thus, anytorque provided to the clip-advancing wire 300 will be transferred tothe mount 346 and then to the distal end 16 of the coil 12. The coil 12will unwind when subject to the torque and effect rotation of the distalend effector assembly 13 corresponding to the input torque.

[0106] Turning now to FIGS. 28 and 29, an alternate construction for thesecond tubular member 310 is provided as a one piece helically cut, e.g.by laser, metal or metal alloy tube 310 a. In order to constrain the cuttube 310 a from elongating under tensile load or from unwinding whensubject to torque, each helical turn, e.g. turn 370 a, is mechanicallycoupled to an adjacent turn, e.g. turn 372 a, via a bridge (or link) 374a extending from one turn 370 a which is permanently interlocked in aspace 376 a in the adjacent turn 372 a. The bridges extend substantiallyparallel to a longitudinal axis A of the tube 310 a and are preferablyomega-shaped (Ω) with a wide free end and a narrow neck. As such, themechanical interlocks are similar to interlocked pieces of a jigsawpuzzle. Preferably one or more such bridges are provided to each turn. Anon-integer number of bridges may be provided to any turn, and anon-integer number of bridges fewer than one may also be provided to oneor more turns. The tube 310 a preferably has a non-circular interiorcross-sectional shape such as cruciform. Such a shape holds a train ofclips therein in a desired orientation. That is, clip 202 (shown inbroken lines) and all other clips in the clip chamber 320 a cannotrotate about the longitudinal axis of the chamber and thus will beproperly aligned for advancement into the jaw-assembly 13 even as thetube 310 a is torqued. Moreover, such shape provides lateral channels378 a, 379 a through which control wires can be located.

[0107] In view of the above, the clevis 14 of the jaw assembly 13 can becoupled to the distal end of the second tubular member 310 (FIG. 26) or310 a (FIG. 28).

[0108] Turning now to FIGS. 30 and 31, a third embodiment of a ratchetmechanism is shown. The ratchet mechanism includes two preferablyhermaphroditic ratchet brackets 430, 432 provided in and coupled to thedistal end 16 of the coil 12. The brackets 430, 432 together define asubstantially rectangular space therebetween which operates as a clipchamber 420 for feeding the clip train in a set orientation toward thejaw assembly 513 (an alternate embodiment of jaw assembly 13, discussedin more detail below). Jaw assembly 13 may also be used. The distal endof each bracket includes a post 450 adapted to engage a clevis 514 ofthe jaw assembly 513 and properly position the chamber 420 relative tothe clevis. Each bracket 430, 432 also includes severallongitudinally-displaced pairs of resilient arms 434. The arms 434 areconnected at their proximal ends 436 to the brackets, with their distalends 438 biased into the clip chamber between the brackets. The clippusher 34 is advanceable through the clip chamber 420 past the arms 434such that the arms 434 are forced laterally against their bias. As theclip pusher 34 is advanced past each pair of arms on the brackets 430,432, the distal ends 438 of the arms once again enter the clip chamber420 and limit retraction of the clip pusher. Thus, each time theclip-advancing wire 30 and clip pusher 34 are advanced to deploy adistalmost clip 202, the clip pusher 34 may be retracted only to alocation defined by the distal ends 438 of the arms 434 proximallyadjacent the clip pusher.

[0109] Referring now to FIGS. 32 and 33, an alternate embodiment of ajaw assembly 513 is shown. The jaw assembly is substantially similar tothe jaw assembly 13, with the following modifications. The proximalportion of the jaws and the distal portion of the clevis have anenlarged combined circumference relative to the remainder of the jawassembly. That is, at the location of the jaw pivot 566 acircumferential ridge 592 is defined by the jaws 518, 520 and the clevis514. This ridge 592 provides the jaw assembly 513 with sufficientstructural integrity at the location of the ridge 592 so that the jawpivot holes 594 and the jaw tang holes 596, 598 (at which control wires22, 24 are attached to the jaws) may be located relatively farther apartthan with respect to jaw assembly 13. Without the ridge 592, the jaws518, 520 and clevis 514 would be unable to define the pivot and tangholes at the shown locations. By locating the pivot and tang holes 594,596, 598 at the ridge 592, the lever arm between the pivot holes and theholes is increased in length, providing a significant increase inmechanical advantage when opening and closing jaws 518, 520. Thismechanical advantage facilitates compression of tissue between the jaws.Where each of the jaws 518, 520 has an overall length L of approximately0.450 inch (11.4 mm), a jaw cup length C of approximately 0.364 inch(9.2 mm), and a distal diameter D₁ of approximately 0.126 inch (3.2 mm),the diameter D₂ across the ridge is preferably approximately 0.138 inch(3.5 mm). That is, the diameter D₂ is preferably approximately 0.012inch (0.3 mm) or slightly more than nine percent (9%) larger than D₁.The distance between the centers of the pivot hole and the tang hole,and thus the length of the lever arm L_(A) (the vertical component)(FIG. 32), is approximately 0.066 inch (1.67 mm). In jaw assembly 13,the length of the lever arm is approximately 0.043 inch (1.09 mm). Thus,jaw assembly 513 provides an approximately fifty percent increase inmechanical advantage over jaw assembly 13.

[0110] Significantly, the diameter D₂ across ridge 592 is approximatelythe same as the diameter of the lumen of the endoscope for which theclip applier 10 is intended; i.e. a 3.5 mm diameter ridge for a 3.5 mmdiameter lumen. Thus, the ridge is within five percent of the diameterof the endoscope lumen, and larger than the remainder of the endeffector by preferably five to fifteen percent.

[0111] It is recognized that it would not be possible to increase themechanical advantage by increasing the entire diameter of the jawassembly to approach the diameter of the endoscope lumen, as such wouldresult in frictional forces between jaw assembly and the lumen of theendoscope which would essentially prohibit tracking the instrumentthrough the endoscope. However, by providing a relatively small surfacearea with the relatively larger diameter, the resulting increase infrictional force is relatively small so as to not substantiallyinterfere with movement of the instrument through the endoscope. Forlarger or smaller instruments, a ridge of similar proportion (i.e., upto fifteen percent greater than the remaining diameter) can likewise beprovided for similar advantage.

[0112] From the foregoing embodiments and examples, it will beappreciated that a flexible surgical clip applier, suitable for usethrough an endoscope is hereby provided. The device is capable ofeffecting a pushing force far in excess of the previously consideredlimitation of approximately 200 grams for a mechanical system sized tobe used through an endoscope. See C. Paul Swain, “What EndoscopicAccessories Do We Really Need?”, Emerging Technologies inGastrointestinal Endoscopy, Gastrointest. Endosc., Vol. 7, No. 2, pp.313-330 (April 1997), discussed above. This substantial force permitsclips to be forced over tissue and thereby makes available clipclamping, closure, and ‘suturing’ in an endoscopic procedure.

[0113] There have been described and illustrated herein embodiments of aflexible surgical clip applier. While particular embodiments of theinvention have been described, it is not intended that the invention belimited thereto, as it is intended that the invention be as broad inscope as the art will allow and that the specification be read likewise.Thus, while particular materials have been disclosed, it will beappreciated that other materials can be used as well. In addition, whileparticular dimensions have been disclosed, it will be understood thatother suitable dimensions can be used as well. Also, while the devicehas particularly been described for use in endoscopic procedures, wherea great need exists for such a device, it will be appreciated thatflexible, non-endoscopic devices are considered within the scope of theinvention. For example, the tubular coil may have a substantiallyshorter length and the device may be used through body orifices such asthe ear canal, the nasal passages, and through the larynx and trachea.By way of another example, elements of the device may have substantiallylarger dimensions and the device can be used through a trocar port.Furthermore, while both jaws are shown rotatable about a clevis, it willbe appreciated that only one jaw need be rotatable relative to theother. Also, while two clip guides, one on each jaw, are shown, it isrecognized that only a single clip guide on one of the jaws is required.Moreover, while the device of the invention is described as having twoend effector wires, it will be appreciated that a single control wiremay be used which is coupled to at least one of the jaws, and the otherjaw may be stationary or mechanically linked to also close and open uponactuation of the single end effector wire. Also, while the device hasbeen described with respect to a clip-advancing wire and end effectorwires, it will be appreciated that reference to the ‘wires’ is intendedto also include non-metal filaments, multifilamentary constructs, suchas cables, and coils. In addition, while the end effector wires whensubject to a tensile force create a compressive force on the tubularcoil which effectively increases its tensile capability to facilitatepushing a clip over clamped tissue without exceeding the tensilelimitation of the coil, it is recognized that other mechanisms may beused to increase the tensile limitation of the coil. For example, apreferably flat and preferably wire ribbon may be coupled to the insidethe coil to limit the amount by which the coil can be stretched.Furthermore, while the ability to provide a relative high pushing forceat the distal end of a clip-advancing wire is disclosed with respect toa clip applier, it is recognized that such capability has application toinstruments other than clip appliers; for example, for endoscopicstaplers, lithotriptors, or any other instrument where it is desired tohold tissue and apply a pushing force, such as a device for tagging. Itwill therefore be appreciated by those skilled in the art that yet othermodifications could be made to the provided invention without deviatingfrom its spirit and scope as claimed.

What is claimed is:
 1. A surgical tool, comprising: a) a proximal handleassembly; b) a distal end effector assembly; c) an elongate flexiblefirst tubular member situated between said handle assembly and said endeffector assembly; d) an advanceable element extending through saidfirst tubular member and having a proximal end and a distal end, saidproximal end coupled to said handle assembly, wherein said handleassembly can longitudinally move said advanceable element relative tosaid first tubular member; and e) a ratchet element located distal saidhandle assembly near said distal end effector assembly, said ratchetelement interacting with said advanceable element to limit movement ofsaid advanceable element.
 2. A surgical tool according to claim 1,wherein: said ratchet limits movement of said advanceable element by,after advancement of said advanceable element relative to said firsttubular member, limiting retraction of said advanceable element to aknown location.
 3. A surgical tool according to claim 1, wherein: saidfirst tubular member is at least as long as the working channel of anendoscope.
 4. A surgical tool according to claim 1, further comprising:f) a second tubular member substantially shorter than said first tubularmember, said second tubular member having proximal and distal ends, saidproximal end being coupled to said first tubular member and said distalend being coupled to said end effector assembly.
 5. A surgical toolaccording to claim 3, wherein: said ratchet element comprises a pawlsituated between said first and second tubular members, and saidadvanceable element includes a plurality of linearly arrangedalternating teeth and notches defined by ramps and substantiallyvertical shoulders.
 6. A surgical tool according to claim 5, furthercomprising: an alignment pawl situated between said first and secondtubular member, wherein said advanceable element includes a longitudinalslot into which said alignment pawl is engaged such that said ratchetpawl and said alignment pawl prevent axial rotation of said advanceableelement relative to said second tubular member.
 7. A surgical toolaccording to claim 6, further comprising: a pawl mount coupled to adistal end of said first tubular member and said proximal end of saidsecond tubular member, said ratchet pawl and said alignment pawl beingcoupled to said pawl mount.
 8. A surgical tool according to claim 5,wherein: said ratchet pawl is resilient.
 9. A surgical tool according toclaim 4, further comprising: a clip pusher coupled to said distal end ofsaid advanceable element, wherein movement of said advanceable member bysaid handle assembly causes said clip pusher to be movable within saidsecond tubular member.
 10. A surgical tool according to claim 4,wherein: said second tubular member is flexible.
 11. A surgical toolaccording to claim 1, wherein: said ratchet element comprises a pawllocated within said first tubular member, said pawl for engaging aplurality of longitudinally arranged notches on said advanceableelement.
 12. A surgical tool according to claim 11, wherein: said distalend of said advanceable element has a non-circular cross-sectionalshape, and a keyhole element is provided in said first tubular member,said keyhole element having a keyhole opening with a non-circularcross-section, wherein said distal end of said advanceable elementextends within said keyhole opening.
 13. A surgical tool according toclaim 12, wherein: said pawl is coupled to said keyhole element.
 14. Asurgical tool according to claim 1, wherein: said ratchet elementincludes at least one bracket element including a plurality oflongitudinally displaced resilient arms which having a proximal endcoupled to the bracket and a distal free end extending radially inwardrelative to said first tubular member.
 15. A surgical tool according toclaim 14, wherein: said at least one bracket is two brackets with aspace defined therebetween.
 16. A surgical tool according to claim 15,wherein: said two brackets are hermaphroditic.
 17. A surgical toolaccording to claim 14, further comprising: a clip pusher coupled to saiddistal end of said advanceable element, wherein said resilient arms ofsaid at least one bracket are configured to engage a portion of saidclip pusher.
 18. A surgical tool according to claim 1, wherein: said endeffector assembly is a jaw assembly.
 19. A surgical tool according toclaim 1, further comprising: a train of clips located distal saidadvanceable element.
 20. A flexible surgical clip applier, comprising:a) a proximal handle assembly; b) a distal jaw assembly; c) an elongateflexible first tubular member having proximal and distal ends andsituated between said handle assembly and said end effector assembly; d)at least one control element extending through said first tubular memberand having proximal and distal ends, said proximal end coupled to saidhandle assembly and said distal end coupled to said jaw assembly,wherein a first actuation of said handle assembly moves said jawassembly between open and closed positions; e) an advanceable elementextending through said first tubular member and having proximal anddistal ends, said proximal end coupled to said handle assembly, whereina second actuation of said handle assembly longitudinally moves saidadvanceable element relative to said first tubular member; f) a clippusher coupled to said distal end of said advanceable element; and g) aratchet element located distal said handle assembly and near said distalend effector assembly which, after advancement of said advanceableelement relative to said first tubular member, limits retraction of saidadvanceable element.
 21. A clip applier according to claim 20, wherein:said retraction is limited to a known location.
 22. A clip applieraccording to claim 20, wherein: said first tubular member is at least aslong as a working channel of an endoscope.
 23. A clip applier accordingto claim 20, wherein: said distal end of said first tubular memberdefines a clip chamber, and said clip pusher is extendable within saidclip chamber.
 24. A clip applier according to claim 20, wherein: saidratchet element comprises a pawl located within said first tubularmember and a plurality of longitudinally arranged notches on saidadvanceable element.
 25. A clip applier according to claim 24, wherein:said distal end of said advanceable element has a non-circularcross-sectional shape, and a keyhole element is provided in said firsttubular member, said keyhole element having a keyhole opening with anon-circular cross-section, wherein said distal end of said advanceableelement extends within said keyhole opening.
 26. A clip applieraccording to claim 25, wherein: said pawl is coupled to-said keyholeelement.
 27. A clip applier according to claim 20, wherein: said ratchetelement includes at least one bracket element including a plurality oflongitudinally displaced resilient arms which having a proximal endcoupled to the bracket and a distal free end extending radially inwardrelative to said first tubular member.
 28. A clip applier according toclaim 27, wherein: said at least one bracket is two brackets with aspace defined therebetween.
 29. A clip applier according to claim 28,wherein: said two brackets are hermaphroditic.
 30. A clip applieraccording to claim 29, wherein: said resilient arms of said at least onebracket are configured to engage a portion of said clip pusher.
 31. Aclip applier according to claim 20, further comprising: a secondflexible tubular member having proximal and distal ends, said proximalend of said second tubular member coupled to said distal end of saidfirst tubular member and said distal end of said second tubular membercoupled to said jaw assembly.
 32. A clip applier according to claim 31,wherein: said ratchet element comprises a ratchet pawl situated betweensaid first and second tubular members, wherein said advanceable elementincludes a plurality of linearly arranged alternating teeth and notchesdefined by ramps and substantially vertical shoulders.
 33. A clipapplier according to claim 32, further comprising: an alignment pawlsituated between said first and second tubular members, wherein saidadvanceable element includes a longitudinal slot into which saidalignment pawl is engaged such that said ratchet pawl and said alignmentpawl prevent axial rotation of said advanceable element relative to saidsecond tubular member.
 34. A clip applier according to claim 33, furthercomprising: a pawl mount coupled to a distal end of said first tubularmember and said proximal end of said second tubular member, said ratchetpawl and said alignment pawl being coupled to said pawl mount.
 35. Aclip applier according to claim 32, wherein: said ratchet pawl isresilient.
 36. A clip applier according to claim 20, further comprising:a train of clips located distal said clip pusher.
 37. A flexible clipapplier device, comprising: a) a proximal handle assembly; b) an endeffector assembly; c) an elongate flexible first tubular member havingproximal and distal ends, said proximal end coupled to said handleassembly; d) a flexible second tubular member having proximal and distalends, said distal end coupled to said end effector assembly; e) a mountcoupled to said distal end of said first tubular member and saidproximal end of said second tubular member; f) at least one controlelement extending through said first and second tubular members andhaving proximal and distal ends, said proximal end coupled to saidhandle assembly and said distal end coupled to said jaw assembly,wherein a first actuation of said handle assembly operates said endeffector assembly; and g) an advanceable element extending through saidfirst tubular member and into said second tubular member and havingproximal and distal ends, said proximal end coupled to said handleassembly, wherein a second actuation of said handle assemblylongitudinally moves said advanceable element relative to said firsttubular member.
 38. A clip applier according to claim 37, wherein: saidfirst tubular member has a length at least as long as a working channelof an endoscope.
 39. A clip applier according to claim 37, wherein: saidsecond tubular member defines a clip chamber for a train of clips.
 40. Aclip applier according to claim 37, further comprising: a ratchet pawllocated at said mount, wherein said advanceable element includes aplurality of linearly arranged alternating teeth and notches defined bysubstantially vertical shoulders and ramps, and said ratchet pawl, afteradvancement of said advanceable element relative to said mount, limitsretraction of said advanceable element.
 41. A clip applier according toclaim 40, further comprising: an alignment pawl coupled to said mount,wherein said advanceable element includes a longitudinal slot into whichsaid alignment pawl is engaged such that said ratchet pawl and saidalignment pawl prevent axial rotation of said advanceable elementrelative to said second tubular member.
 42. A clip applier according toclaim 37, further comprising: a clip pusher coupled to said distal endof said advanceable element.